Typically, III-V nitride-based semiconductors are widely used in fabricating semiconductor devices because of their large energy band gap. However, due to the large energy band gap, high contact resistance may be seen between a metal electrode and a semiconductor interface or contact. For example, consider gallium nitride (GaN) including a p-type GaN layer having magnesium (Mg) dopants that form Mg—H complexes with hydrogen. In this case, the Mg—H complexes lead to passivation of the Mg dopants, which results in high contact resistance between the metal electrode and the contact of the p-type GaN layer.
Additionally, wider market adoption of the semiconductor devices may depend on the fabrication cost. To reduce the fabrication cost, contacts used in the semiconductor devices may need to be made compatible with complementary metal oxide semiconductor (CMOS) fabrication technology. Existing method for fabricating CMOS compatible contacts includes usage of aluminum (Al), which is a CMOS compatible material. However, Al has bad adhesion to the p-type GaN layer. Another existing method for fabricating CMOS compatible contacts includes fabricating an interfacial layer of metals with high work function on the p-type GaN layer. However, even with the presence of the interfacial layer the contacts may have poor electrical characteristics and may not be CMOS compatible.